Method of treating glycerin.



UNrTnD STATES PATENT OFFICE.

SAMUEL HENRY FLEMING, F CAMDEN, NEW JERSEY, ASSIGNOR TO .E. I. DU PON'J.DE

NEMOURSPOWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION'OF NEWJERSEY.

siding at Camden, county of Camden, and

State of New Jersey, have invented a new and useful Improvement inMethods of Treating Glycerin and Products Produced Thereby, of which thefollowing is a full,

clear, and exact description.

Polylnerized glycerin or poly-glycerin'is a term used for a glycerin inwhich, as is generally supposed, two or more of the glycerin moleculesare combined to ether. There are several ways in which this is producedat the present time; thus it has been produced by heating alone, whichis very slow and not effective and produces a prodnot which is quiteimpure. In order to accelerate the reaction, certain alkalies have beenused, among which caustic soda, NAOH, is the most rominent. The use ofcaustic soda, while it accelerates the reaction, has a tendency toproduce by-products, which are deleterious to the glycerin. I havecarried'on a line of workwith respect to this so-called polymerizedglycerin or poly-glycerin and I am led ,to believe that there is not onla union of the molecules of the glycerin ut also that a certainproportion of the water of the combiningmolecules is driven ofi, thusproducing a condensation product of glycerin.

The glycerin treated as beforedescribed has certain advantages in thatit may be used in the manufacture: of nitro-lglycerincompounds forexplosives which will have a lower freezing point thanwherenitroglycerin made from glycerin not so treated is used. I am also ledto believe, from many tests, that nitro-glycerin made from glycerin sotreated is less liable to decompose than is nitro-glycerin made fromglycerin not so treated. In Working on this line I have discovered thatif instead of using an alkali, I use an acetate which may be any of theacetates, preferably sodium acetate, NaC I-I O but otherwise treated asbefore described, the product will be produced with much lessdecomposition of the glycerin than occurs where alkalies are used.Preferably I add the acetate in quantity of onehalf to one per cent. ofthe weight of the glycerin. This mixture is subjected to a temperatureof 275 to 280 centigrade. The waterwhich separates in the reactionSpecification of Letters Patent. Application fil ed May 27, 1909. SerialNo. 498,749.

7 METHOD or TREATING GLYCERIN.

Patented Sept. 6, 1 910.

*is distilled off, leaving a mixtureof this glycerin, which is generallyknown as polymerized glycerin or poly-glycerin, and

sodium acetate in Which about seventy per cent. of'the glycerin isso-called polymerized.

- The detailed statement of the process and the rationale of the sameare as follows:

nrssonn The glycerin used is what is known as dynamite glycerin, whichis a highly purified glycerin containing 98 to 99% glycerin. Thereaction according to which'glycerin is condensed to diglycerin is asfollows:

3 s 3""H2O: 3 5) 2 (0H)4 I on on. ornon (lHOH inen (anon en,

-n,o=' t on on bit,-

(inert tnon (ii-non (IJHZOH Triglycerin is formed as follows: 30,11, on2n,o= e rn ,0, on

01; on on ornon bnon hnon on, (anon I on on tn, (IJHOH -2n,o= ll-10H(IBHZOH tH. on on t ilHOH L (lH OH JHoH ta s In the same Way tetra,penta, hexa, etc., glycerin would be formed by the elimination of 3, 4,5, etc, molecules of water respectively.

All these products are conveniently and concisely grouped under thecommon term V Cohn, 3rd edition, 1903. As a matter of fact, whenglycerinis polymerized by the method at present known, practically all of thatconverted goes to the form of diglycerin and only a small percentage totriglycerin. Probably no more than traces pass into tetraglycerin, andthe higher products, if, in fact, any at all suffers this change.

Adherence to the following directions will enable any one to carry outmy process: A suitable Vessel of glass, metal or other material whichwill stand the working temperature is selected, with an outletsuflicient in size to permit of the ready exit of the water vaporsformed, and the small amount of glycerin which accompanies them. Thisglycerin is of a quality suitable for the manufacture of ordinarynitroglycerin. The glycerin is weighed and from this weight, the properamount of anhydrous sodium acetate is computed and added, although it ispossible to obtain results with the crystallized salt. Of course, it isimmaterial Whether mixture of glycerin and sodium acetate is effected inor outside of the heating essel. The contents of the vessel are nowraised to a boiling temperature, which eeaise' 1. The hereinbeforedescribed method of treating glycerin, which consists *in mixing withthe glycerin an acetate and subjecting the mixture to heat.

2. The hereinbefore described method of treating glycerin, whichconsists in mixing with the glycerin an acetate, and subjecting themixture to heat, the acetate being in quantity from one-half to one percent. of the weight of the glycerin.

3. The hereinbefore described method of treating glycerin, whichconsists in mixing With the glycerin sodium acetate, and subjecting themixture to heat.

4. The hereinbefore described method of treating glycerin, whichconsists in mixing with the glycerin sodium acetate, and subjecting themixture to heat, the sodium acetate being in quantity from one-half toone per cent. of the weight of the glycerin.

In testimony of which invention, I have hereunto set my hand, at Camden,on this 21st day of May, 1909.

SAMUEL HENRY FLEMING.

Witnesses:

AUGUST SEEMAN, F. B. HoLMEs.

